1. Field of the Invention
The present invention relates to a method of position detection and more specifically to a method of sensing the position of a object using a "no (physical) contact" type light beam reflection technique.
2. Description of the Prior Art
A previously proposed technique generates a laser beam using a semiconductor type laser source and induces this beam to reflect off an object toward a camera which includes a one dimensional type sensor or pickup. The image formed on the photo sensitive arrangement of the sensor is used to induce each of the photo sensitive elements to react in accordance with the intensity of the light which impinges thereon and produce electric signals which vary accordingly.
The position of the peaks of each of the signals generated is supplied to a floating digitizer and used to develop a reflected image which is used to determined the distance of the object.
However, these arrangements have suffered from the drawback that the output of the laser source sometimes tends to become excessively strong and/or is totally reflected back into the pickup. This induces the signals produced to be excessively strong and to saturate the system in a manner which crops off the top of a wave signal formed using the image signals and prevents the position of a peak value thereof from being located. As a result the position of the object cannot be accurately detected. Even if the amplification degree is lowered under these conditions the saturation phenomenon is not overcome and the erroneous nature of the detection persists.
On the other hand, it sometimes happens that the level of the laser output falls excessively low level or the object is excessively far away. Under these conditions, the weakness of the received signals induces the situation wherein position of the central peak cannot be determined among those produced by the noise even if the level of signal amplification is increased the noise components of the signal are also increased and still the central peak cannot be discerned. Accordingly, under these conditions also accurate determination of the distance of the object (viz., position thereof) cannot be accomplished.